Catheters are sometimes provided with electrodes for selectively stimulating and/or sensing electrical activity in body tissue, such as the heart. For example, a catheter may be inserted into the cardiovascular system of the patient, through the superior vena cava (SVC), and into the heart so as to achieve placement of an electrode or electrodes in desired position(s) within the heart or adjacent a chamber of the heart to evoke a response of tissue to an electrical signal applied to the electrodes. The catheter is generally a hollow tube extruded from a resilient polymeric material, such as a silicone or polyurethane rubber, with one or more passages or lumens extending longitudinally through the tube. Electrodes are typically formed of annular metal bands that are disposed about the circumference of the catheter at predetermined, axially-spaced locations between the proximal and distal ends of the catheter. Conductive leads pass through one or more of the lumens from the proximal end of the catheter to the more distal locations of the electrodes and are electrically connected to the metal bands, e.g., by soldering, welding or the like. An example of such catheter electrodes is disclosed in U.S. Pat. No. 3,995,623.
It is important that the conductive leads be reliably electrically connected to the metal band electrodes to insure safe and proper operation of the catheter after it has been inserted into or implanted in the body of a patient. Reliable electrical connections are especially critical in the case of catheters which have a plurality of electrodes and catheters which are bent and flexed so as to be maneuvered through sometimes twisted and tortuous body lumens, such as the vascular system including the heart. Failure of the electrical connection to a catheter electrode in such circumstances can have catastrophic consequences for a patient, especially, for instance, in the case of electrodes in temporary or implantable defibrillation catheters such as the defibrillation catheter disclosed in copending U.S. patent application Ser. No. 08/625,872 filed Apr. 1, 1996 and assigned to the assignee of the present invention, the entire disclosure of which is incorporated herein by reference.
It is therefore a principal objective of the present invention to provide a catheter with one or a plurality of electrodes which has reliable electrical connections to a conductive lead or leads extending through the catheter from the electrodes to the proximal end of the catheter and a method of fabricating the catheter in a cost effective manufacturing process.